Certain naturally occurring materials contain a hydrocarbonaceous component which upon heating will release a hydrocarbon product which is useful as a feedstock in petroleum processing. These "hydrocarbonaceous solids" such as oil shale, tar sands, coal and diatomaceous earth, may be "retorted", i.e. pyrolyzed, in reactor vessels having various designs. Following the pyrolysis of the hydrocarbonaceous solid to extract the volatile components, "a pyrolyzed solid" remains which contains a carbonaceous residue which may be burned to yield heat. This heat may be used to supply heat for the pyrolysis of fresh hydrocarbonaceous solids.
The inorganic residue that remains after the combustion of this carbonaceous residue is recycled in some retorting processes as "heat transfer solids," i.e., the hot burned inorganic residue from the combustion is mixed with fresh hydrocarbonaceous solid, and the heat provided is used to heat and pyrolyze the fresh material. Alternately, the heat transfer solid may be a particulate solid other than the inorganic residue remaining after the combustion of the pyrolyzed material. Such alternate heat transfer solids include particulate solids such as, for example, ceramic compositions, sand, alumina, steel or the like. Such materials are generally heated in the combustion zone and then transferred to the pyrolysis zone either alone or mixed with the burned inorganic residue. In many instances these alternate heat transfer solids serve as supplemental heat transfer material in combination with the hot inorganic residue formed in the combustion zone.
The use of a pyrolysis zone in combination with a combustion zone is a typical feature of a number of different processing schemes for hydrocarbonaceous solids. See for example, U.S. Pat. Nos. 4,199,432; 3,703,442; and 3,008,894. In order to provide sufficient heat to produce synthetic petroleum feedstocks from the hydrocarbonaceous solids noted above, it is frequently necessary to employ supplemental fuels in the combustion zone. The design and arrangement of the process steps also is important to insure the efficient transfer of heat between the two zones. The present invention is concerned with an arrangement of process steps which are intended to make a commercial retorting operation more efficient.